1. Field of the Invention
The invention relates generally to secure documents and more particularly to systems and methods for providing tactile features on secure documents.
2. Description of the Related Art
Vision-impaired persons benefit from the inclusion of standardized ‘readable’ tactile features on documents and other items which enable them to determine important information regarding the item. For example, the Braille system of writing, one form of standardized tactile feature, has opened to the vision-impaired all the wealth of knowledge previously accessible only to those with unimpaired or correctable vision. Braille has also been used to enhance non-literary items such as signage, thus enabling the vision-impaired to interpret better such items and providing to them a greater degree of independence. Tactile features have also found use by those with unimpaired vision, but under circumstances where normal visual reading or inspection proves inconvenient or difficult, as when an otherwise readable item is poorly lit. For example, so-called “night writing”, a forerunner to Braille, was created by Charles Barbier de la Serre for use by Napoleon's soldiers to communicate silently and without light at night.
One innovative use of tactile writing has been the inclusion of tactile features on secure documents such as banknotes and identity documents such as passports. In International Patent Application No. WO/2000/051824 published Sep. 8, 2009 [“WO824”], the present applicant discloses a system and method for making banknotes having a tactile feature identifying a denomination of the banknote, thus enabling a vision-impaired person to determine easily the value of a handled banknote. This feature also enables a person with unimpaired vision to determine a banknote's denomination without requiring visual inspection, for example when adequate illumination is unavailable or when thumbing through the contents of a wallet or purse.
One challenge in providing readable tactile features on widely-circulated secure documents such as banknotes is that their frequent use ordinarily involves the repeated application of pressure against the tactile feature via a fingertip of a person or particularly by components of mechanical counting machines and currency dispensers. Consequently, the tactile features must be sufficiently durable if they are to remain substantially undamaged for the expected lifespan of the document. WO824 provides a solution to this problem wherein a sheet material forming the document is embossed so as to create the tactile features, and these are then reinforced in order to provide durability. Before being able to reinforce the embossments, however, it is first necessary to have a reliable and efficient means of producing the embossments.
Known methods for producing embossments in sheet materials typically involve equipment configurations which do not enable individual adjustment of each of the many embossments to be produced in the sheet material, either during an initial configuration of the equipment or during document production.
It is known in the art of document production to use numbering presses having numerous separately mountable numbering heads. The use of modular numbering heads enables greater flexibility in making adjustments as well as preparing a desired arrangement of printing members. The tolerances required for such numbering heads are greater (i.e. more lenient) than those required for the production of the embossments described above (e.g. ±30 μm), however, as such numbering heads are used typically to transfer ink from an ink cylinder to the sheet material and not to produce reliably-sized embossments.
There is thus a need for an apparatus and a method for producing in sheet materials numerous embossments which economizes time and effort to enable production at the tolerances required for durable tactile features on secure documents and which economizes time and effort to make adjustments and to change document configurations during a production run.